HttpWebRequest的从AudioPlayerAgent(HttpWebRequest fr

我创建播放无尽的音频流的应用程序。还有的是，我可以查询得到当前播放曲目的标题和艺术家独立的Web服务。我想要做的就是查询服务，每20秒钟，然后设置相应的曲目名称/艺术家。目前我使用背景AudioPlayerAgent，使流，可以在我的应用程序之外播放。这里是我到目前为止的代码：

public AudioPlayer()
    {
        if (!_classInitialized)
        {
            _classInitialized = true;
            // Subscribe to the managed exception handler
            Deployment.Current.Dispatcher.BeginInvoke(delegate
            {
                Application.Current.UnhandledException += AudioPlayer_UnhandledException;

            });
            trackTimer = new Timer(TrackTimerTick, null, 1000, 5000);
        }
    }

    public void TrackTimerTick(object state) {             
            // Create a HttpWebrequest object to the desired URL.
            HttpWebRequest trackRequest = (HttpWebRequest)HttpWebRequest.Create("<stream url>");
            // Start the asynchronous request.
            IAsyncResult result = (IAsyncResult)trackRequest.BeginGetResponse(new AsyncCallback(TrackCallback), trackRequest);
    }

    public void TrackCallback(IAsyncResult result) {
        if (BackgroundAudioPlayer.Instance.PlayerState == PlayState.Playing && result != null) {
            try {
                // State of request is asynchronous.
                HttpWebRequest trackRequest = (HttpWebRequest)result.AsyncState;
                HttpWebResponse trackResponse = (HttpWebResponse)trackRequest.EndGetResponse(result);
                using (StreamReader httpwebStreamReader = new StreamReader(trackResponse.GetResponseStream())) {
                    string results = httpwebStreamReader.ReadToEnd();
                    StringReader str = new StringReader(results);
                    XDocument trackXml = XDocument.Load(str);

                    string title = (from t in trackXml.Descendants("channel") select t.Element("title").Value).First<string>();
                    string artist = (from t in trackXml.Descendants("channel") select t.Element("artist").Value).First<string>();
                    if (BackgroundAudioPlayer.Instance.Track != null) {
                        AudioTrack track = BackgroundAudioPlayer.Instance.Track;
                        track.BeginEdit();
                        track.Title = title;
                        track.Artist = artist;
                        track.EndEdit();
                    }

                }
                trackResponse.Close();
                NotifyComplete();
            } catch (WebException e) {
                Debug.WriteLine(e);
                Debug.WriteLine(e.Response);
            } catch (Exception e) {
                Debug.WriteLine(e);
            }
        }  
    }

一个网络异常，随时我尝试读取从HttpWebRequest的响应抛出。这是这样做的正确方法？有没有人有任何建议，我怎么能解决这个问题？

Answer 1:

你不关闭HttpWebResponse ，这是必要的。此外，还有过载XDocument.Load()采用一个Stream ，所以你不需要使用StreamReader的。

编辑：对不起，我忽略了Close()在结束通话。但是其他的评论仍然适用。

如果不解决这个问题，至少它使你的代码看起来更干净：

public void TrackCallback(IAsyncResult result) {
    if (BackgroundAudioPlayer.Instance.PlayerState == PlayState.Playing && result != null) {
        try {
            // State of request is asynchronous.
            HttpWebRequest trackRequest = (HttpWebRequest)result.AsyncState;
            using (HttpWebResponse trackResponse = (HttpWebResponse)trackRequest.EndGetResponse(result)){
                XDocument trackXml = XDocument.Load(trackResponse.GetResponseStream());

                string title = (from t in trackXml.Descendants("channel") select t.Element("title").Value).First<string>();
                string artist = (from t in trackXml.Descendants("channel") select t.Element("artist").Value).First<string>();
                if (BackgroundAudioPlayer.Instance.Track != null) {
                    AudioTrack track = BackgroundAudioPlayer.Instance.Track;
                    track.BeginEdit();
                    track.Title = title;
                    track.Artist = artist;
                    track.EndEdit();
                }
            }
            }
            NotifyComplete();
        } catch (WebException e) {
            Debug.WriteLine(e);
            Debug.WriteLine(e.Response);
        } catch (Exception e) {
            Debug.WriteLine(e);
        }
    }  
}